150 likes | 409 Vues
Crude Oil. Separating Oil into Fractions & Cracking Hydrocarbons 10.02 & 10.03 p170-173. Learning Objectives. Explain how crude oil can be separated through fractional distillation (CC17) Video http://www.youtube.com/watch?v=26AN1LfbUPc. Crude Oil.
E N D
Crude Oil Separating Oil into Fractions & Cracking Hydrocarbons 10.02 & 10.03 p170-173
Learning Objectives • Explain how crude oil can be separated through fractional distillation (CC17) • Video • http://www.youtube.com/watch?v=26AN1LfbUPc
Crude Oil • A mixture of of many different chemical compounds. Separated by fractionaldistillation • Nearly all the compounds in crude oil are hydrocarbons. Hydrocarbonsare compounds which contain the elements hydrogen and carbon. • Most of the hydrocarbons in crude oil are alkanes. • These alkanes all end in –ane e.g. methane • The general formula for these compounds is: • CnH2n + 2
How does Hydrogen and Carbon bond together? • Covalent bonds=Kovalenta bindningar • Covalent bonds=share electrons • Hydrogen has only 1 electron, in its outer shell • Carbon has 6 electrons, 2 in its first shell and 4 in its outer shell
Bonding • How many electrons does an atom need in its outer shell to become stable=happy?
How many electrons does an atom need in its outer shell to become stable=happy? • Answer=8 electrons. Except Hydrogen that is happy with 2 electrons in its outer shell. • This means that one carbon atom will share electrons with 4 Hydrogen atoms. • The Carbon borrows one atom from each Hydrogen and ends up with thinking that it has 8 electrons in its outer shell=stable=happy;). • Each Hydrogen borrows one electron each from the Carbon, thinking that it has 2 electrons in its outer shell=stable=happy.
Hydrocarbons One Carbon atom can also bond together with another Carbon atom, they then share 4 electrons between them but need 2 Hydrogen atoms each too in order to think that they have a full outer shell.
Crude Oil See chapter 2.05 p34 in your Chemistry book for more about covalent bonding. Crude oil cannot be used for anything useful because of all the different sizes of hydrocarbons inside of it.
Alkanes Saturated hydrocarbons - they contain as many hydrogen atoms as possible
Low boiling point Burns easily Runny Fractional Distillation Thick Hard to burn High boiling point
Fractional Distillation Poster (p171) • Make a poster about Fractional Distillation and how it is used to separate crude oil. Include the following information: • Labeled picture of the column • Temperature labels (high to low) • Names of the products removed at each fraction • Clear explanation of how the mixture is separated using all the keywords below: • Heating Evaporates Cools Condenses • Mixture High Boiling Point Low Boiling Point • Hotter Cooler Vapour Hydrocarbon
Extra Questions You have 4 minutes to answer all the questions giving as much detail as you can: 1. How does the length of the hydrocarbon affect the boiling point and viscosity of the hydrocarbon? 2. A hydrocarbon catches fire easily. Is it likely to have long or short chains? Why? 3. ‘Light’ crude oil is pale and runny, often produced in Nigeria and Saudi Arabia. ‘Heavy’ crude oil is dark and thick, often produced in Venezuela. Why is ‘light’ crude oil likely to cost more than ‘heavy’ crude?